Lewis acid BF3 modulates inner helmholtz plane to promote Zn (002) plane adsorption and inhibit dendrites

Zinc-ion batteries (ZIBs) exhibit great potential as energy storage devices due to their low cost and excellent safety. However, the growth of zinc dendrites and hydrogen evolution reaction on the zinc anode severely hinder their industrialization. Here, we modified polyacrylamide (PAM) gel electrolyte with a highly electronegative boron trifluoride diethyl ether complex (BFEE) containing a source of -BF 3 to suppress parasitic side effects on the anode of quasi-solid-state ZIBs. As a Lewis acid, -BF 3 interacts strongly with the interface between anode and electrolyte, where it effectively modulates the inner Helmholtz plane (IHP). Specifically, the electrostatic interaction between -BF 3 group and Zn 2+ ensures uniform Zn 2+ distribution in the PAM/BFEE gel electrolyte, effectively inhibiting the concentration of local electric fields at the interface and suppressing the growth of Zn dendrite. In this work, we have explored the optimal addition amount of BFEE in PAM (2 wt%) and obtained the gel electrolyte of PAM/BFEE-2 %, which exhibits excellent mechanical properties with a fracture stress of 121 kPa and a tensile strain up to 2745 %. Moreover, the modulated IHP promoted the preferential adsorption and growth of Zn 2+ on the Zn (002) crystal plane that with higher adsorption energy in the assembled Zn|PAM/BFEE-2 %|Zn battery. This full battery achieved over 1000 h of cycling stability at a current density of 1 mA cm −2 , confirming that the introduction of highly electronegative BFEE into PAM can effectively suppress dendrite growth and achieve long-term stability of the zinc anode.